I went through an agent.
I have very 2 interviews in 2 days, both lovely and friendly.
then... complete silence...
the agency asked for feedback and the reply was " sorry we are on holiday so we had no feedback"
We had to chase them to finally after 3 weeks have very basic feedback (they basically offered the job to someone else and pretended to be 'on holidays")
I think when you ask a candidate to be available immediately for 2 interviews in a row, you should come back to them quickly as well (at least when you know) without having to be chased and please be honest...